Highway 99W bridge to undergo construction
Major delays are coming to Highway 99W in Washington County this summer.
A bridge repair project is slated to begin in August on the highway bridge across the Tualatin River, in between Tigard and King City to the north and Tualatin to the south.
According to the Oregon Department of Transportation, the $2.15 million project will include replacing the bridge joints and installing new concrete surfaces on the northbound stretch of the busy highway. Motorists will need to brace themselves for periodic closures, congestion and delays.
"Right now, the bridge carries about 15,000 vehicles a day," said Don Hamilton, a longtime spokesperson for the Oregon Department of Transportation.
This is an old bridge, as Hamilton noted. The southbound span opened in 1929, while the northbound span opened in 1955. Because the department's traffic counting only goes back to 1986, he said, it's hard to calculate vehicle-per-day usage when the spans first opened — but traffic, obviously, has increased tremendously since then.
Tualatin was among the fastest-growing cities in the state in the 1970s and '80s; Sherwood experienced a growth spurt in the 1990s and 2000s; and King City, Tigard and Bull Mountain have all added significant numbers of new residents since the turn of the millennium.
Some work has been done on the bridge over the past 30 years, according to Hamilton.
"In 1992, there was a deck overlay," he said. "In 1999, there was a railing retrofit. That means they upgraded the railings on the side of the bridge."
In 2003, work was done on the undercarriage of the bridge.
Speaking of the upcoming bridge improvements, Hamilton said, "We are trying to do what we can to make this corridor safe. This has been in use for a long time. Look at where it is. This is a very busy section of road, especially as this area has grown up in the last 10 to 20 years. We're trying to do what we can to make it as safe and as efficient as we can."
Hamilton said the bridge project, set to begin in August, will remove the existing deck overlay on northbound Highway 99W. A new deck overlay will be installed.
"We're going to replace the bridge joints," Hamilton said. "Bridge joints are the places where sections of the bridge come together and join."
Paving will take place on the bridge approaches. Other repairs, and fencing will take place.
Hamilton noted that cracks underneath the bridge that are found by inspections can be addressed with a deck overlay.
Motorists will need to be aware of changes.
"People should prepare for significant traffic impacts," Hamilton said. "This is a busy bridge. It's a busy community. When you squeeze that northbound bridge, you take away half of the capacity on that bridge. We're going to see some delays. People are going to notice this closure. It's going to be very obvious."
Hamilton said the construction work "will extend the life of the bridge" by as much as 30 years.
"We're expecting this will last a good long time and we can keep this bridge going," Hamilton said. "We do a thorough inspection of all bridges every two years. This will certainly prolong the need to replace the bridge, which is ultimately what you do when a bridge starts to fail."
According to ODOT, when work begins, motorists should expect the following:
• Periodic daytime and nighttime lane closures on Highway 99W northbound.
• A roughly 30-day single-lane closure on Highway 99W northbound at the Tualatin River, leaving one lane open at a time. Travelers should expect significant traffic congestion and delays.
• Bicyclists will travel in the lane of traffic through the work zone.
• Detour signs will direct freight trucks onto Southwest Tualatin-Sherwood and Roy Rogers roads to avoid bridge construction.
ODOT also advises that construction will produce noise. A 24-hour nighttime noise hotline will be set up before construction takes place.
Traffic delays, Hamilton said, could be up to 30 minutes during peak traffic times.
The highway isn't closing altogether. Hamilton said one northbound lane will be open at all times during the project.
Hamilton has advice for motorists this summer.
"As this closure is coming up, people need to come up with plans to go around (the project), to find an alternate route or expect delays," he recommends.
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